SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55ec01759c7a299be1c9a216449e4d01443bf1ad0cfc17ad24c8f763fd16dac5' 
  AND token = 'zVsmh4PrpoNoDmevaAZUI1ijzr6W8H0xbooslbsaiG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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