SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68d49bb59a8ddcd9c0b3632b7285a601f8da8888ef944e22405df3910b240a9f' 
  AND token = 'vDUEoa7KoJCUgMOguG/zelGrmV3VDzAPeWqHSDRjNCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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