SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67ec98a58320a2cd566dc59119edc2073fa2b4dbaee120f04ccc5796652e59f0' 
  AND token = 'wYMsXVZaFmkrzZlzSDx8Qz9aSPz8EHK5+Gbo2b3nauU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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