SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe861c27bba24b760ac22e23a895a9264472ae265b43cc4fb8e987371ccd789e' 
  AND token = 'kfEXffS1QhK2zUPSMYrRXJWlQj8xBxXI9t6zT9iDqCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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