SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c3b5bf403fab781dcd89bdd51f126d69122bb74098911a2dbff435411c42b751' 
  AND token = 'Nqg+kXgIQ5Kf+XX/P7Y9ziPzdSOmrbHtJ/Q6qtQZGRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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