SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e33540fe3de725eb4375ed5cdbfbc68c74255947b1129ab2b125a262657b9af' 
  AND token = 'Y6X/hP8mBqPeSIEBVWhS1Zg++x8seF3MAaPFnoWyJeY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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