SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acc7daf29f064ed0eec3b30235035e44558a6fe44384554106848ca93fe12ba9' 
  AND token = 'k9lmGfi6rYrUXLJlK7izRslS+MKVHRIvH3CJj7ccxhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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