SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d81a13ded13e595e4cb7f86c0cd2934efc3e072144fd0c62b408779ee573909' 
  AND token = '0Esb7gO/KFKv0STlEqK7T/9FrniSB7Vyg9cO+JPMGGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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