SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2461b4681f5036118b8e5ea16746596f71b0717124a61f874cb85656d6596da7' 
  AND token = '4OGLea/PUHFFdFBnB1t8XNwIj8qSWKSFkP7EL1XUqkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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