SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b329dac63775781cd0570dbe6e0804039b6b984572774aec12f820c93e55359' 
  AND token = '+DC3SPhIxm0WKJ5VFvidhQFQJD/5xg5nj/muJOyJgHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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