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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd635af310597608a73e254cb1fafa776c72b1d19b5721b61cc0d8bda0716f598' 
  AND token = 'UFy/Y73dXQi9LfpiAaJSDvpRS+JefVWFn4O6Y6/dc+k=' 
  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"
    }
  }
}