SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e290fbe621c1bf431712a7351c6983526bd063301b495924a767f7605986bca' 
  AND token = 'aKW0WXWo36Cnsh7NjfgwcOnTl2nYD+/KHaNPIoYYDK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}