SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '684215e17929d2b011e884b91e41005891546f45ef4f8fa55d185017c6b69538' 
  AND token = '+ZpVOc2jeBZzlaPZZ8GFM1EZQ3wjbXTAnwdwcWibSNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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