SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db806cf983675503f261f9b4e385d772946b78581861fd83999da1665ff86245' 
  AND token = 'vX4+EXwDZkjUaxmXhi8uqseKYOA2P3yYUJkcyse/Nog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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