SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ff1594a0354024ca4249b81d0cf45687252eb1ee0173a76bc71e923c73b4437' 
  AND token = 'wRH6Ysc++AQ+5v/Z0sVAXMzYyN2Y1XjpP/YVQpsRGMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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