SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1731a37e8410c18b826fc6dd8d98a566f0ed1346340e930406d3c622f9eb274' 
  AND token = 'C3yuZyTJj4KUGwDLyCzF/lzVB1FVfexsDC/aeK9OPC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00098

JSON explain

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