SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc53d055ac7452090730c2f721676cf77e496ea25e1a4915dec61f39a89564fe' 
  AND token = 'ufjsiSAgQR9WAjwS8NQXveE9yV4ROl/AOaJCefLjVV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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