SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bd27ce713d7ff86ae0a3911f47add710d934b7a9afd83e19c1e3b6bfea18247' 
  AND token = 'ACOXISzZyszgRDFEl43HuT/4HKFOBoqN3D/KCfDTt54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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