SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dd1654fda19bee75fb7f47c7de00e3b75a5b844d3e1e1f3032b4d363d7c72f15' 
  AND token = 'THaUm7GCpiIJd2D46+awIs64+zDf/nAnGPUYP6YnWqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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