SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac6bcd630f9553e1034830744ccafe4cf38a48b8430b255b585f142cdeb04799' 
  AND token = 'yGta/d1IbBSPOktYcFpQbIp4Zkvd784zWdOCLWtzYX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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