SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82fec613d40ccf6632d907552409214a0915f19c7070c44c82d8300f8a216623' 
  AND token = 'GVSt6Vj+qKWFaP1QqxCjl8Tg3Ypm49w5ENPJ38vHXKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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