SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0a39142fe5dce79e9187066d7c33814c9844f3e32d5db2944e652cb2c545a644' 
  AND token = 'ffBsIA/rZwPMzI3HUiM2dzlc9fQqDO/NjLK25CiSFYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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