SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82f885a06337a395b048315bd07c3e2716d7b201eeb3aa9949104c361ab551ea' 
  AND token = '2u59Cx0icJCFkpcMH8nrWOQ4w+FlrexbW1ak46oWeTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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