SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '90b43124cc7b33875d932577143b9fabd427c2d2f41f2b7292044d47e9f5fd24' 
  AND token = '/K+Zc9aq3tXdC6+Zubs/qs0PZQJp8evSMVfCQVrJGEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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