SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9cbce53594b7efc69e4bb388b35e89b2b35f97e24e1797ac833466c346cc4174' 
  AND token = '+dPRScTjXCCKFFMSMNduar6iVWHM/C/dClkZYR7OrJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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