SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a5598ba85bd5e19c7c2c5c1fd11840280422444c330afd9f4b9fc8054c0fb41' 
  AND token = 'i+fB2/ww7qrP1Vhv1ck7p/y3W2YHIe8cFR1FimbnafY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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