SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21308a16631b9f0b3c1bf9ab06ceb3f90d0fab6460d878c541ed003d5e80efd5' 
  AND token = 'rmKL4sZ4cb46AP+xY/HwLAjsirphh/8JPkg7lMYgQ4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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