SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5421c8d655dddb7e5c2dabbe7bfa42734a81879429ed3c6ea49be9cb8a3136f' 
  AND token = 'zOa72zFr8GOCHZD32ItIZ78qDRoOHsxsDqW+35oHx90=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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