SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c79f8c939494522dca3dc827286ac47e06fc6fb6ab6e08ac2c381a444b329bbf' 
  AND token = '8Y8mqZBYVoXgPmw0xznJPfe576w+ApZOuTSvhBabadg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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