SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8064ad722e29a499972e041153bbf54610726fb8cf4eba2999df3e1f7034c100' 
  AND token = 'GdEK17mj/jbYZCWBumZhM9LGaaEBfevonKXiH97xgNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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