SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16b198307ebd53bdbb047b0520fd73a78a99406610f2060ef7366f30b7846952' 
  AND token = 'oZKUBJAWSaI/p76UZm1GBqKXhSxnCyLXTyHHF8kWniI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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