SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b21d0681df536ced8a93a99acce1b8a982c5bb2cf047d316d72bc0bf5c34ff9d' 
  AND token = 'XorJZk+YONWt4+SC0y+phopqH80SYzDwGPpgKRtZ0/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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