SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b9581bb1205d013edf9a6f55997ba156d1615e276e3343db9109f66d3171bfa' 
  AND token = 'piheDj5mJfVFtRjEtdmYTy26NoxL++CZUCLxFlU8YZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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