SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '718279e51264011c384021bf5a663ae2b2533d9089bc28973ea9aeaef79acdb5' 
  AND token = '2axkEJB8OKWdNzDWv/G13zY+0RYBCawBxr1ktvVbfS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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