SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '395a266b0d0074d88a015ac29877fb4fe4a7ade194152df22cc2baf507bb48b6' 
  AND token = 'fN2UZCwuYrJVA4LuxaVFidUvqTUT/9wjSgG+XQ/iszY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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