SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0b288a54b010ce98e0088f3e0c6715839b3781b51b01509d2333173c3bb5b20' 
  AND token = 'LUrj4wY3VvW69N3KZH3fPQ1m9C1eoDWIONyVrpzfOIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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