SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4fa19a1f0fb71686903fa5e7193b965ddcc90c7cb711eeb464740847d8fa9f4' 
  AND token = 'ACJ1ecHckzJ6DohD7HsNvn6vD3uoxL+qlpPu8MhWRXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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