SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '031131f719e6d05f341c9668d356704a0b14032d96b6a48b3292332353179ab2' 
  AND token = '3SFA9n9Oo7V9ssl+ZjcxTBKthSGFGqWaQYXb0wSotgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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