SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4118ca785ed9f73f08bd6d54f5616a86f70cda0a09e75d5fbef0f99c10fb7fc' 
  AND token = '42vGfdlWkF6MjrVYF9CjM0XuuDCrnWzkEnvoOm7DdGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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