SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '318549df582b3b86944c79db99d44d84122ee5e1cd51ae69e80649e15fe78669' 
  AND token = 'EERIg3eDoVjELyuZr6VCdyLf7pr7xVqfuUFgq00e4eI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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