SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '746200b603b1db55bdfea54d7f28b685d23614a0b6f2cd74f87c30bd6f804c30' 
  AND token = 'p2xmBwb+uB/+RIzzkmD7N3JDwcfitLxqpBtecnX6S8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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