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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7a6849eb32411e0170b575d9edc3b7655dc4435b8cfa8e721ddd1a9b27e3012' 
  AND token = 'VPYdoa5zZ4uFN1GsuNER4dHkA9NrtosEv1NTsQcEH6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}