SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6254d414d9d5890e90c017e9f39715bfd29098cb83d69756cdc3ba9af6e14a1e' 
  AND token = 'hzZd1z3vPcOs41/V3OBzYFpKBvXHxi/ZnZtmhuCynM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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