SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e5578a6cb71c4e5c8630fd4b8760209cdd0bd3e0204851bb7e9b50745cf9a822' 
  AND token = 'DkyqwQ2GWLZ9XXYjj7+VN+RHUz6JiDnOHwh7lHGfg14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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