SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ed116160394f98ea815ae7787253ee94177d4bca635dce41519efe87b6cae27' 
  AND token = 'kmmzBobs+lqR5Ygp8WMZWNsMvguPkabyMUnT4Iu+JPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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