SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '465a481fb2087bb83e4974fd3b4be012e71016266f10cde413e928833f74f991' 
  AND token = 'QbcrYwfSf00wlfycE7hcBdUoc3VTQKv0AHvChmE2Jfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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