SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd18ecca5142c222491331876e06f1da22ce39d48d34db8b5d60e3854ed7e2011' 
  AND token = 'NhT5KNM37zkzPdQwhU4vFwRMRKOB70Y0J/+/50ACLHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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