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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc5b0eb5927a7948e078fa86cecddb50d776a7840e29824979cd7d11f5a09e47' 
  AND token = 'kn4vwxUW7GwsU4sVFx2ihQKsLFnJMAsHqSL91qczkOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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