SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '307ce8e2c938c6e3f82158e088ca037770b30f93bd935b0880196f8f302d7d10' 
  AND token = 'z0aGvcR2eNcsiec8A5DQgjwwA/uXLVWxO7CXxiUXP/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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