SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e587b8e3869c1b35659ad6ac6139c1375f7c310a504982776e86e396d8e45174' 
  AND token = 'Pn+vXtfjJt9nTDq36gO2uql6wpUpqRrAjbigzeqhDVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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