SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20a6781f57bb2d90d971281c8d1a366964fffc09b70c7f940192c1c4af7d4ac2' 
  AND token = 'rIcOGYLNmzirxddn8gjWyV5bIokZjVENzQ/Wj/G1FQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}