SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5586279ce234efc94e1e44a14af9c87c5ea383530e5f77cde21df2689d49a055' 
  AND token = 'IPrD5ZzThO3ELZm/i0mBibMVAsBuzWM0pceFttEzYPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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