SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7394cbda3d24027116ff79badf30139a78eb39528e8d79b21306587ab3f80d45' 
  AND token = '7/pCXTsayzeO3wpdhyTB+tWrZ4fSQgVEVNhlPQ1DsDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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