SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0c6f36d86dc8ad4d55e3ddc71a166225d914c25717f4750608232903606bec88' 
  AND token = 'KkaxdeFPmLDH6R4ayQDvNcyXtuyTEie75ZtdgxV17NE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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