SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fed07eaf8d6b98144a74a3b0a2dca229bf27bb89165d4a6aa417b679765712c1' 
  AND token = 'Ywi+7a+R010y4xunM6lvgi8wcLd5RzqbqYhCoG+nWSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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