SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af4fadfdc8a4501b3bf9aa38c452ecb7e3c76a722916a6c45d20a774681c7ede' 
  AND token = 'XyGQFvP6qz/ZUchuXFFfzwTauSz6fXSJJDJDqAYVr3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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