SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0968a86e8227b18118c3ab002383255db007353f1f2493e0d9403bc0ea7e6499' 
  AND token = 'IGs+lY3guKjHqZIZJRh/kCdxFCXEjfeN3CNCORl/5+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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