SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '455f53b2898b96a8c4f620d9372f07ecbe904613e1bfd23c3ae8b7e9e987dc8c' 
  AND token = 'rfd7mG2vKAVYHZypfk+E/1Dk/pIR5jX3hWRMPuq5RiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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