SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e6b088c75b564e94008998e5fc98102c61a903da37c3becf23fa529d32e1201' 
  AND token = 'QeUGXSI2KLJr6a/pY9EkElKA0TV9SArrddbd/qjuj28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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