SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cef71847759b9680f813edcb919e7f716bc5edb97ada5bd94ca2d265f7fa2d0' 
  AND token = 'GGKDrOypP0Xyqj4feM4XNvVzdJtSsdx9osIFvWeDuf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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