SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3c1c1e86146d2ab47a11e5ab7c10b4c12a179656918cb76942fa96050fa22f6' 
  AND token = 'jyYaN4jcM6KLjSsghJIHvdRqphYlCkSdd3uAr5+iegI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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