SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6efed3e4667426d0989ac6db12a3963849b4c75d10b5f85a5f1e53e488282d6d' 
  AND token = 'Az1EKyjjGjyGUnFdlfVHToy8ZjLmksVHGvwjqgM+izA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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