SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ed8bf894c1485eb9d199dbffde0b596959068c5996ec996635c61f5f4f32c86' 
  AND token = 'Tl3xvX3QgEySsf1ycghG+n86JLWyivmtMaWkf9qyJaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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