SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fc349013decf0842f267f96f83a112165a86f6b99c495fa00cfca254bdecdc99' 
  AND token = 'hBlP16acVDO7CJZJY9qkFoHGQ7zIJ57XKAQCkLa5Vd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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