SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '811b1f346f0239e0152cd640fce774ab73df7721039cc807ad422e98b85fdccb' 
  AND token = '3JbEmAXEX9yCIi+11O0wh9DU9rkmWXjsY0r3B1gFRY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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