SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e12086331c4f303acaf4800a208ba3448b163e675fd533d74f11fcd610e9fc57' 
  AND token = 'TfdwsQoJLGv/C6LZ/uN6Inqg/6BXfa8Vw0gDTB2++cw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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