SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6fb69a40a50d235780c26685273252503ff4aa2a62dae133be463b9fd6a6773f' 
  AND token = 'H+LwVNftuBXTUhnbbXF6U3XYSlLzGL82sElV4eRKIgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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