SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '742d26657eaeea414b40ddbeb1e7596a0b8d8bf1910fb38790ff4ce58c44b8c6' 
  AND token = 'uVD+JCLlZMhOtQrmfwKvDVx5DF2NBP9DSagLFWzjc0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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