SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8375ad72ba439a1ec06c08ddc27e1f0c5a08af7804b0944849b01aef55e8e01a' 
  AND token = '8zrHH3Rdj2cazY8qZO+u1WvXX98MiMp77H3RwPjKfBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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