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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bd5a9e7cb4ca35a69c9463d13913b1a7c4dbaa6d719e8c5e75e07aee367d8bb8' 
  AND token = 'mlW09NxoyIk1OTpYgzNqhLX3Ps019xuikqY0vPy+6Lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}