SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd6280c3099f0684963ffa5edee12d8d820c572e616941246dd9dbe6c045a0642' 
  AND token = 'k7KcZJFrN0EHT+EkIDMc79HgI9RVj3IWgBKXQR5o3g8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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