SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '92b0be9ecf74f0bf9f7e30f54d7dc69bf807d0a82058fdb7631c18980b97dc10' 
  AND token = 'rprNKXiV+zSZDGvT6g5EuoUrJrPLVlmX1pxQzznmMbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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