SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '68a051a825244b3bac68800614932229f87c4c3b6b53511c77daa378192c032d' 
  AND token = 'Vaz/FSRreJkJ/6yjwwxiHSg6oVCacu/MIGCzX/KsRGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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