SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4267824dcfe3be01bc95fbab3514346e520b5978dcdc0d9528caf045a3867bfe' 
  AND token = '1NOKv1g9JS/hE+cK4aqAD9IfWElNtlMrXInGkjecGHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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