SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a206566490997fc512302bcce6f1a0bb9f543e869d68d6d1cc9b3f4c10cf2eb7' 
  AND token = 'Kaph/1CPqX+T4zd+LsFUGKa9JFdy3YnAyINYVfhjuLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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