SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a737232de480b41e0286cf333e281a3043f7573f7228de0933640fa7b46945b' 
  AND token = 'zG5uKXFxOW/Wl3Z3vkMOZxF9rYs/U7tyC+HihPVtYag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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