SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '000f616cb4337e57850bf8a697adb21755567fc82357fccb6853c036897cb4da' 
  AND token = '0ZY4yIYPUODdArmbis8Fu7I4zjBu3ioRczUrSu7g8XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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