SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2faba033b9868abf7321b041a6dfd79bcb3fd5e5ed0f6e83fc5f58f54008136' 
  AND token = 'HJtLNjHkVkVyHKGSm7D0AvLFN6+WjCgwn/IhOS22PDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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