SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0204850281dd4070d92226bc172c3ed279bd30ed4be325fb2d577d851cb16106' 
  AND token = '4hSWqFOFU8DBAInicIuNu5GNW/pwbtS9m/a20YW/af8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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