SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '362ae45da1aed3aa1c75195fc746a62cee90283d92fdea3857a398641235344a' 
  AND token = 'RgWtQ4uggee3sAGiLMz1XwwIZGWUsjQNEIFS4cmDIJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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