SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccf97f2224c158f757e3f8d431341e867b0ddf9ae09c820756057f8f502c6a43' 
  AND token = 'HDsyk5vCO+e8Xqw3VmCFkx6uDKRgtQiPOWbZnwfGwrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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