SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4e9a41faeabc28adc1c3008145966170a33b37cfb46e510056eb78078fe4782' 
  AND token = 'YkG269R8omqURv6rTTppomKVvi8vgib+qvdJbjSnLRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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