SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dfb4a53715528b32c39c639c0aea51496c1ff3ed6453d1ad3c14a539579b70f' 
  AND token = 'L8GV+Po4SNzrladWuR+/V5C+UqSYuFBQ/kEZvv4U0B8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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