SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '588d5b3243cf288a01754cddedb25dd0fe74ab5a3c7aa5d5481ec31f90ff9397' 
  AND token = 'BLuuzCsyju5uCwtu1UKRW4LKpoHKFwueJF2OmgHyrJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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