SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '853952ea3e95daf2383f9660b14fe177793792f908459061c22ea2375bd79e9e' 
  AND token = 'XjvHgVYoquKQvr2adLewQhEzR3paV/m7wHQin6Nmq78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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