SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6588c0fc06b563a4a4d35d78efda8140f9d8177cb60ebe1e740a71645b95280' 
  AND token = 'G0TkP/8k8y88jZviuwBPH7qeLjpkZRq32dIhakCKs28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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