SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97cff7964a5d9dafea721bb70086b1656974602e977a45fdf80292983949da5f' 
  AND token = 'R6ZLdyjJOUQ5Bhaq/0/PKfakyfSRA/NnfZbZUvZHwNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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