SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b629c5cf9f6a1330d888f432fc81f48bd57921ebc9254ff84b14d735100ea13' 
  AND token = 'FcNznkmC39tomuyRIiWxO0WXZDmU5v+2ynMzlGLyy8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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