SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78acc11c3ee740b697f616701fc9cefb1419fd8f246a9dff8b60aa9f4529ff8a' 
  AND token = 'swfDAHCn/Ljtu7G+P5GvK1w21AhsIMCnhRSrXPq40mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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