SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52a88666dd231d46c1683a498011745e9028dfaf622c4a42aab789449616964b' 
  AND token = 'ixoV6Y8fcfFZIlJLgzHwpiVAV1bcbbFksyLjdPf/j5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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