SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4e6ff6da15b26ee2dd6cf0885f1574d426cc8338e20f24d0b128386750223ab' 
  AND token = 'KFPw77OAQFliGQBTyQZzx+GeGZu/B82yqnk4wjui22Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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